首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   41739篇
  免费   915篇
  国内免费   13篇
  2020年   253篇
  2019年   247篇
  2018年   3819篇
  2017年   3103篇
  2016年   2587篇
  2015年   432篇
  2014年   433篇
  2013年   1630篇
  2012年   1163篇
  2011年   3008篇
  2010年   2837篇
  2009年   1891篇
  2008年   2264篇
  2007年   2714篇
  2006年   578篇
  2005年   696篇
  2004年   628篇
  2003年   560篇
  2002年   475篇
  2001年   826篇
  2000年   844篇
  1999年   602篇
  1998年   252篇
  1997年   228篇
  1996年   201篇
  1992年   486篇
  1991年   426篇
  1990年   494篇
  1989年   410篇
  1988年   389篇
  1987年   371篇
  1986年   392篇
  1985年   442篇
  1984年   341篇
  1983年   286篇
  1982年   219篇
  1979年   323篇
  1978年   258篇
  1977年   207篇
  1976年   201篇
  1975年   299篇
  1974年   346篇
  1973年   350篇
  1972年   275篇
  1971年   243篇
  1970年   208篇
  1969年   229篇
  1968年   288篇
  1967年   251篇
  1966年   273篇
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
821.
The representation of quantification over relations in monadic third-order logic is discussed; it is shown to be possible in numerous special cases of foundational interest, but not in general unless something akin to the Axiom of Choice is assumed.  相似文献   
822.
Pigeons were trained on a pair-comparison task in which left versus right choices were reinforced following different sequences of two center-key stimuli. Choice accuracy was higher when retention intervals occurred after the entire sequence than when they separated the two stimuli comprising it, and this effect occurred independently of whether the initial and terminal stimuli came from the same or different dimensions. The initial stimulus from the prior trial was a source of proactive interference only in groups for which the retention interval separated the two sequence stimuli. By contrast, differential delay-interval behavior was observed only in groups for which the retention interval followed presentation of the entire sequence. These results indicate that coding processes in delayed discriminations are influenced by the location of the retention interval, and that response mediation affects retention performances if the reinforced choice can be determined prior to the interval.  相似文献   
823.
Toward a theory of verbal behavior   总被引:6,自引:6,他引:0       下载免费PDF全文
This paper is a reply to an accompanying set of six commentaries by Sidman; Hayes and Barnes; Schusterman, Kastak, and Reichmuth; Tonneau and Sokolowski; Lowenkron; and Moerk. Those commentaries were prompted by our article “On the Origins of Naming and Other Symbolic Behavior” (1996), which was, in turn, followed by 26 commentaries and a reply. In the course of the present reply, we further develop the naming account to embrace more complex verbal relations such as same, different, more, and less. We also examine what we see as the lack of conceptual coherence in equivalence theories, including relational frame theory, and the disparities between these accounts and the findings from empirical research.  相似文献   
824.
This paper discusses two forms of separability of item and person parameters in the context of response time (RT) models. The first is separate sufficiency: the existence of sufficient statistics for the item (person) parameters that do not depend on the person (item) parameters. The second is ranking independence: the likelihood of the item (person) ranking with respect to RTs does not depend on the person (item) parameters. For each form a theorem stating sufficient conditions, is proved. The two forms of separability are shown to include several (special cases of) models from psychometric and biometric literature. Ranking independence imposes no restrictions on the general distribution form, but on its parametrization. An estimation procedure based upon ranks and pseudolikelihood theory is discussed, as well as the relation of ranking independence to the concept of double monotonicity.I am indebted to Wim van der Linden for bringing Thissen's (1983) paper to my notice, and to Martijn Berger, Frans Tan, and the anonymous reviewers for their constructive comments on earlier drafts of this paper.  相似文献   
825.
Davidson's explanation of first-person authority in utterance of sentences of the form 'I V that p ' derives first-person authority from the requirements of interpretation of speech. His account is committed to the view that utterance sentences are truth-bearers, that believing that p is a matter of holding true an utterance sentence, and that a speaker's knowledge of what he means gives him knowledge of what belief he expresses by his utterance. These claims are here faulted. His explanation of first-person authority by reference to the requirements of interpretability is committed to the view that all understanding involves interpretation. This is argued to be a misconception of understanding and of speaker's meaning. Davidson's account involves acceptance of the cognitive assumption that normally when a person V s that p , he knows that he does. This assumption is challenged. Throughout, Davidson's conception is compared and contrasted with Wittgenstein's.  相似文献   
826.
In a replication of a quasi-experiment by Skarlicki and Latham (1996), we investigated the effect of training union leaders ( N = 25) in the administration of organizational justice principles on union members' ( N = 177) perceptions of their leaders' fairness and the members' subsequent citizenship behavior toward their union. Despite the fact that the union members were also shareholders of the company, the results were replicated. Union leader training increased members' perceptions of their leaders' fairness as well as union members' citizenship behavior directed both toward the union as an organization (OCBO) and fellow union members (OCBI). Organizational justice was found to partially mediate the effect of the training on OCBO, but not OCBI.  相似文献   
827.
Receiver-operating characteristics (ROCs) were examined in three recognition memory experiments. ROCs for item information (i.e., was this word presented?) were found to be curvilinear. However, ROCs for associative information (i.e., were these two words presented together?) were found to be linear. The results are in agreement with the predictions of a dual-process model that assumes that recognition judgments are -based on familiarity and recollection. Familiarity reflects the assessment of a continuous strength dimension and is well described as a signal detection process, whereas recollection reflects the retrieval of qualitative information about the study episode and behaves like a discrete threshold process. The results showed that memory judgments about items relied on a combination of recollection and familiarity, but that judgments about associations relied primarily on recollection. Further examination of the associative ROCs suggested that subjects were able to recollect that old pairs of items were in the study list, and, under some conditions, that new pairs were not in the study list.  相似文献   
828.
Hartman and Hasher (1991) used a garden-path task in which younger and older adults generated the final word for each of a series of high-cloze sentences. Under instructions to remember the final word, the experiment included critical sentences for which the generated word was replaced by a new, to-be-remembered target. Using an implicit priming task, the first experiment replicated a basic finding: Younger adults showed priming only for the target words, whereas older adults showed priming for both the generated and target words. Two experiments explored boundary conditions. One showed that an additional sentence that interpreted the new target word enabled older adults to narrow access to only the target word. The provision of additional time following the introduction of the new target word did not. Specific information, not more time, is required for inefficient inhibitory mechanisms to clear the recent past from memory.  相似文献   
829.
The purpose of the present study was to develop the Toddler Behavior Screening Inventory (TBSI) for rapidly assessing maternal reports of toddler behavior problems. The TBSI is a 40-item measure intended for use by pediatricians, psychologists, and other child-care professionals. A group of mothers (n = 312) rated the initial 93-item TBSI in terms of behavior frequency and parental perception of the behavior as problematic. Following item elimination, 40 items were retained due to being both frequent and problematic at all toddler age levels. Data were obtained with a new sample of mothers (n = 581) and showed the TBSI to possess good reliability and validity.  相似文献   
830.
The hippocampus, which is critically involved in learning and memory processes, is known to be a target for the neuromodulatory actions of steroid hormones produced by the adrenal glands and gonads. Much of the work of B.S. McEwen and collaborators has focused on the role of glucocorticosteroids and estrogen in modulating hippocampal plasticity and functions. In addition to hormones derived from the endocrine glands, cells in the hippocampus may be exposed to locally synthesized neurosteroids, including pregnenolone, dehydroepiandrosterone and their sulfated esters as well as progesterone and its reduced metabolites. In contrast to hormones derived from the circulation, neurosteroids have paracrine and/or autocrine activities. In the hippocampus, they have been shown to have trophic effects on neurons and glial cells and to modulate the activity of a variety of neurotransmitter receptors and ion channels, including type A gamma-aminobutyric acid, N-methyl-D-aspartate and sigma receptors and N- and L-type Ca2+ channels. There is accumulating evidence that some neurosteroids, in particular pregnenolone sulfate, have strong influences on learning and memory processes, most likely by regulating neurotransmission in the hippocampus. However, the hippocampus is not the only target for the mnesic effects of neurosteroids. Associated brain regions, the basal nuclei of the forebrain and the amygdaloid complex, are also involved. Some neurosteroids may thus be beneficial for treating age- or disease-related cognitive impairments.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号